Pressure operated circuit controller



I Octgl, 1 935. H. R. JUSTUS PRESSURE OPERATED CIRCUIT CONTROLLER FiledAug. 29, 1932 [0mer]E.(7211:2 21:

ATTORNEY Patented a. 1, 1935 PRESSURE OPERATED CIRCUIT CONTROLLERHomerlt. Justus, Kansas City, Mo. Application August 29, 1932, SerialNo. 630,889

4 Claims.

for motor driven devices and more particularly to means for controllingthe motor circuit of said devices.

In the present instance I have shown my invention applied to apparatusfor feeding pulverized or slack coal into furnaces, boilers and thelike, whereinthe coalis conveyed by a feeder from a hopper into thefurnace or boiler. The

feeder is driven by anelectric motor which heretofore continued tooperate even after the hopper had been emptied, thereby imposingunnecessary wearand tear upon theworking parts.

The object of my invention is to'provide simpie and inexpensive meanswhereby the motor circuit is automatically .opened before all of thecoal has been fed to the furnace or boiler, and in order that saidinvention may be fully understood, reference will now be had to theaccompanying drawing, in which;

' Fig. l is a broken vertical sectional view of the feeding apparatusequipped with my invention. Fig. 2 is a detail longitudinal section ofthe controlling means.

Fig. 3 is an enlarged sectional view of the upper portion of thecontrolling means, taken on line 3-3 of Fig. 1.

Fig. 4 is a diagram of the motor circuit. Referring in detail to thedifferent parts, 2

designates a hopper which communicates with a feeder comprising a screw4 and a trough 6 for conducting the coal from the hopper to the furnaceor boiler, not shown. 8 designates an electric motor for driving thescrew 4. The foregoing may be of any well-known or preferred form.

Referring now more particularly to my motor circuit controlling means,i0 designates a pressure actuated element consisting in its present formof a lever mounted upon a fulcrum I 2 carried by ears i4 projecting fromthe lower end of a protective tube l6 located within the hopper 2.

The inner end of the lever I0 is connected to a plunger It which extendsupwardly through guides 20 in the tube l6 and into a case 22 fixed tothe upper end of said tube I6.

24 designates a switch, preferably of the mercury type, which is mountedupon one end of an 50 arm 26 pivotally connected at its opposite end tothe interior of the case 22. The arm 26 has an aperture 28 through whichthe upper end of the plunger I 8 projects as shown by Fig. 3.

When the device is in operation the arm 26 is 55 held in raised positionby means of a coil spring My invention relates generally to controllers30 interposed between said arm and a collar 32 fixed to the plunger l8.

34 designates a manually controlled switch adapted to remain in eitheropen or closed position. Said switch 34 is adapted to close against 5 acontact 36 and is provided with a push-button 38 which projects upwardlythrough an aperture in the top of the case 22.

As shown by the diagram Fig. 4, the switch 24 and the contact 36 arearranged in the motor 10 circuit 40, while the switch 34 is connected toa loop 42 extending around the switch 24 and connected to one side ofthe motor circuit.

The operation briefly stated is as follows: When the hopper 2 issupplied with fuel the 15 weight of the latter depresses the lever ID tothe full line position shown by Fig. 1, thereby causing. the inner endof said lever to raise the plunger l8 to the full line position shown byFig. 3. As the plunger I8 moves upwardly it,'throughthe 20 intermediaryof the spring 30, raises the arm 26 and the switch 24, thereby causingthe mercury in the latter to flow downwardly into contact with theswitch terminals 43 and thus close the motor circuit 40. After asufiicient amount 25 of coal has been fed from the hopper 2 to relievethe lever IU of pressure the latter is immediately forced to the fullline position shown by Fig. 2 and the dotted line position shown by Fig.1, by an expansible spring 44 interposed between 30 the adjacent guide26 and the enlarged lower portion of the plunger l8. The foregoingoperation carries the plunger I 2 downwardly thereby permitting the arm26 and the switch 24 to descend by the force oi. gravity to the dottedline 35 position, Fig. 3, so that the mercury switch 24 will uncover thecontacts 43 and thus automatically open the motor circuit 40. The motorcircuit remains open until the hopper 2 is replenished with suflicientcoal to again depress 40 the lever to. In some instances, however,enough coal may lodge under the lever ID to prevent the same from movingdownwardly and eflecting the reclosing of the switch 24. Under thesecircumstances the circuit 40 may bemanually closed by 45 forcing theswitch 34 into engagement with the contact 36, thereby providing a pathfor the current around the switch 24 through means of the loop 42. Whenthe circuit is closed as stated the motor 8 again starts to operate andjust as soon as the'coal lodged beneath the lever III has moved downinto the trough 6 and permitted the lever Hi to be forced downwardly tothe full line position, Fig. 1, by the weight of the coal thereon saidlever pushes the plunger I8 upward- 17, thereby causing the same toeffect closing of the switch 24 and opening of the switch It.

Prom the foregoing description it is apparent that I have providedcontrolling means which is well adapted for the purpose intended, andwhile I have shown and described a preferred arrangement of theinvention I reserve all rights to such changes and modifications thereofas properly fall within the spirit and scope of the invention asclaimed.

Having thus described my invention, what I claim and desire to secure byLetters Patent, is:

l. lncontrolling means of the character described, the combination witha hopper, a feeder for conveying material from said hopper, an electricmotor for driving said feeder, and a circuit for said motor, of a switchfor controlling said circuit, a pivotally mounted member arranged withinthe hopper and adapted to be held in a depressed position by thematerial, a plunger adapted to be held in such position by the depressedlever as to close the switch, and spring means for shifting said plungerto another position so that the switch may open the circuit.

2. In controlling means of the character described, the combination witha hopper, a feeder for conveying material from said hopper, an electricmotor for driving said feeder, and a circuit for said motor, of aself-opening switch for controlling said circuit, a pivotally, mountedmember arranged within the hopper and adapted to be held in adepressedposition by the material. a plunger adapted to be held in such positionby the depressed member as to close the switch. a d spring means forshifting said plunger to another position so that the switch may openthe circuit.

3. In controlling means of the character described, the combination witha" hopper, a feeder for conveying material from said hopper, an electricmotor for driving said feeder, and a circuit for said motor, aprotective tube extending downwardly into the hopper, a member pivotallymounted at the lower portion of said tube and adapted to be held in adepressed position by the material in the hopper, a plunger pivotallycon- 5 nected at its lower end to the pivotally mounted member andextending upwardly through the protective tube, a self-opening switchadapted to be held in closed position by said plunger when the pivotallymounted member is held in a dem pressed position by the material, andspring means for forcing the plunger downwardly so that said switch mayopen when the pivotally mounted member is relieved of the weight of thematerial. g

4. In controlling means of the character described, the combination witha hopper, a feeder for conveying material from said hopper, an electricmotor for driving said feeder, and a circuit for said motor, aprotective tube extending m downwardly into the hopper, a memberpivotally mounted at the lower portion of said tube and adapted to beheld in a depressed position by the material in the hopper, a plungerpivotally connected at its lower end to the pivotally mounted a memberand extending upwardly through the protective tube, a self-openingswitch adapted to be .held in closed position by said plunger when thepivotally mounted member is held in a depressed position by thematerial, spring means a for forcing the plunger downwardly so that raidswitch may open when the pivotally mounted member is relieved of theweight of the material, a loop extending around the self-opening switchand connected to the motor circuitfand a switch 35 adapted to bemanually operated to close said loop, said last-mentioned switch beingarranged in the path of the plunger so that the latter may open theformer when the pivotally mounted member is depressed.

noun a. .ms'ros.

